Pressure exchange apparatus



Patented Oct. 24, 1950 UNITED STAT PRESSURE EXCHANGE APPARATUS GeorgesD-arrieus, liouilles, France, assignor to Aktiengesellschaft Brown, Boveri &.Cic, Baden, Switzerland, a joint-stock company Application July 29, 1947, Serial No. 764,499

In Switzerland July 29,1946

'SJClaims. (circa- 1.)

and outlet openings for controlling the flowaof the respective gas streams through the cells i asmcession. The known rotary pressure exchangers have-various advantages over other apparatus, for example a turbo-compressor, whichfcould be employedto effecta pressure exchange-abetweentwo gas streams but have not attainedtthe effieiency which might be expected fromanan- .alysis of the operating conditions.

.It has been proposed to .take advantageof the compression'andexpansion waves whicheare' set up in the several cells in succession by so locating the openings in the stationary end walls that each end ofa cell is closed-substantially at the instant of the'arrival at that cell-end of a compression or an expansion .wave. The resulting increase in efficiency was substantial but was still much less than had been anticipated. I have identified one factor which lowers'the predicted efficiency ,of'a rotary pressure exchanger as the centrifugal force which disturbs the travel of pressure and expansion waves along the cells, thereby leading to losses.

Objects of the present invention are to provide pressure exchange apparatus of thetcellular type which substantially eliminate losses from centrifugal force, and which thereby operate with. increasedeificiency. An object is to provide pressure exchange-apparatus. in which the cellularassembly is stationary and the flow of gases therethrough is controlled by rotatingend walls'or distributors. More':specifically; objects are to provide pressure In the drawing, the reference numeral l iuentifies the casing or outer peripheral wall of a cylindrical array of cells formed by longitudinal partition walls'2 which extend radially from the outer wall I toan inner cylindrical wall 3. The casing l is located between and axially alined with the cylindrical inlet and discharge casings 4,,5, respectively, these casings having coaxial cylindrical conduits 6, 1, respectively secured therein by a plurality of radial webs 8. The low pressure gas stream in the inlet conduit 4 is indicatedby the arrows L, and the high pressure gas stream in the coaxial inlet conduit 6 is indicated by the arrow H. The low pressure gas is compressed within the cells and discharged as a stream of annular cross-section within conduit 5,'as is indicated by the arrows L, and the expanded stream of high pressure gas flows off through conduit 1, as indicated by the arrows H.

The flow of gas through the cells is controlled by rotating distributors keyed to a shaft 9 which is located at the axis of the casing I and journalled in bearings I!) mounted in the end walls or flanges H which extend inwardly radially from-the peripheral wall 3 of the cell assembly. The inletdistributor comprises a disk l2 provided with a pair of diametrically located openings l3 for admitting lower pressure gas to the cellsand a second pair of diametrically located openings I4 for admitting high pressure gas to the cells, the openings l4 being the outlet ends of a bifurcated conduit l5 having a cylindrical inlet end rotatable in the outlet end of the high pressure supply conduit 6. The exhaust distributor is of similar construction and comprises a disk H with a pair of outlet openings l8 for the compressed gas and a pair of outlet openings I9 for the expanded gas, the openings [9 being the inlet ends of a bifurcated conduit 20 which terminates in a cylindriexchangers of the type stated which include a a:

stationary and cylindrical array of cells, and

apertured end walls or distributors which are rotated by a motor or by the flowing streams of gas.

These and other objects and'the advantages of the invention will be apparent from the following specification when taken with theaccom'pany'ing drawing in which:

' Fig. v1 isa central longitudinalsectionithrough a pressure exchanger embodying the invention;

'Fig. 2 is a perspective view of the same, with parts of the casings broken away to show the cell assembly and the distributors; and Fig. 3 is a fragmentary perspective view of a modified form of rotary distributor.

cal section rotatable in the inlet end of the con- The distributordisks l2, I! are secured to the shaft 9 which is rotated by a motor 2| through gearing 22. Theihigh pressure gas streams enter the cells with a radial component when, as'shown inFigs. 1 and 2, the side walls of the bifurcated passages of the distributors are parallel to the' gas. A distributor of this type, as illustrated in Fig. 3, comprises a disk l2 and bifurcated con- .duit l5 ;of helical form.

The same cycle: of. operationstakes place-in the several cells in sequence, and there are two complete cycles for each rotation of the illustrated distributors which are provided with two sets of openings for each gas stream. Two or more sets of openings are desirable for pressure and mass equalization but it is possible to operate with only one set of openings. Assuming that the cycle starts with low pressure gas entering the cell through an opening [3 of the inlet distributor l2, and the other end of the cell open to the expanded gas conduit 1 through an outlet opening [9 of distributor disk I! and the conduit 20, the low pressure gas forces the contents of the cell (consisting of an expanded body of the high pressure gas) out at the rear of the cell. The discharge end of the cell is closed by the distributor disk I! when the discharge of the expanded gas is completed, thereby setting up a compression wave which moves forwardly in the cell and brings the contents of the cell to rest. The rotating distributor disk [2 closes the inlet end of the cell upon the arrival of the compression wave at the inlet end, thus trapping gas within the cell under l1 higher pressure than that of the entering stream of low pressure gas. Further rotation of the distributors brings an inlet 14 into line with the cell, and high pressure gas flows into the cell. This sets up a compression wave which travels towards the discharge end of the cell and sets the 'body of gas in motion. An outlet opening 18 moves into alinement with the cell as the compression wave reaches its discharge end, and the gas to be expanded pushes the compressed gas in front of it and into the compressed gas conduit 5. The inlet end of the cell is closed by distributor disk I2 when the scavenging of the compressed gas from the cell is completed, thus setting up a decompression wave which travels through the cell to bring the contents to rest. Upon the arrival of the decompression Wave at the discharge end of the cell, the distributor disk I! closes the cell which now contains an exforwardly panded body of originally high pressure gas. An

outlet opening 19 then moves into alinement with the cell, and the expanded gas is discharged through conduit 20 into conduit 1, thus setting up a decompression wave which travels towards the inlet end of the cell, The cycle is completed upon the arrival of this wave at the inlet end of the cell, and an outlet opening [3 of distributor disk l2 moves into line with the cell to initiate another working cycle.

Pressure exchangers constructed in accordance with the invention operate with high efiiciency as the centrifugal forces set up in the rotary distributors have little or no influence upon the travel of the compression and expansion Waves along the cells.

The apparatus as illustrated and described is the presently preferred form of the invention but it is to be understood that various changes may be made in the mechanical constructions and arrangements of the parts without departure from the spirit of my invention as set forth in the following claims.

I claim:

1. Pressure exchange apparatus comprising a cylindrical assembly of cells extending longitudinally of and about an axis, a high pressure and a low pressure gas conduit at the inlet end of said cell assembly, discharge conduits for expanded high pressure gas and compressed low pressure gas at the opposite outlet end of said cell assembly, means including distributors at each end of said cell assembly for controlling the connection of the respective ends of the cells in succession to said conduits to generate compression and expansion waves in the cells when connected to the low pressure and high pressure conduits respectively, and means supporting said cell assembly and said distributors for relative rotation about said axis; characterized by the fact that said high pressure conduit is within and coaxial with said low pressure conduit, and said expanded high pressure gas conduit is within and coaxial with said compressed low pressure gas conduit.

2. Pressure exchange apparatus as recited in claim 1, wherein said cell assembly is stationary and said distributors are supported for rotation.

3. Pressure exchange apparatus as recited in claim 1, wherein said cell assembly is stationary and said distributors are supported for rotation, said distributors including helically arranged gas passages for connecting the ends of said cells to said high pressure gas conduit and said expanded high pressure gas conduit respectively.

4. Pressure exchange apparatus as recited in claim 1, wherein said cell assembly is stationary and said distributors are supported for rotation, said distributors including helically arranged gas passages for developing rotative forces from the gas stream flowing through the same.

5. Pressure exchange apparatus as recited in claim 1, wherein said cell assembly is stationary and said distributors are supported for rotation, in combination with motor means for rotating said distributors, said distributors including helically arranged gas passages for eliminating radial components from the gas streams delivered to said cells.

6. A pressure exchanger comprising a cylindrical assembly of cells extending longitudinally of and about an axis, a pair of inlet and of discharge conduits for two streams of gas under different pressures, said inlet and said discharge conduits being respectively at opposite sides of said assembly of cells and the conduits of each pair being coaxial, and means comprising rotary distributors for controlling the connection of each cell in succession to the several conduits, each distributor having REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,045,152 Lebre June 23, 1936 2,264,126 Wydler Nov. 25, 1941 2,399,394 Seippel Apr. 30, 1946 FQREIGN PATENTS Number Country Date 844,442 France Apr. 24, 1939 

